1. Field of the Invention
The present invention relates to a caged nut for retaining a threaded nut in limited lateral and rotational movement, and more particularly to a caged nut comprising a housing having a means for restrictively retained the vertical walls from outward movement.
2. Description of The Prior Art
Caged nuts are nuts enclosed in a box-like housing that is adapted to be mounted over a bolt opening in a surface. The cage holds the nut in place and prevents rotation or other movement of the nut when a bolt is threaded into the nut. Caged nuts are particularly useful when the nut is to be placed in an inaccessible position where it cannot be reached by hand or a wrench.
One problem with a caged nut is that threading a bolt into the nut exerts a torsional force on the nut and this in turn exerts a spreading force on the side walls of the cage. Unless the side walls are constrained in some manner, the walls eventually spread so far apart that the nut can turn in the cage.
In the past, several different devices have been developed to retain the vertical walls of a housing from spreading outwardly when a bolt is torqued into the threaded nut contained in the housing. One such method involves forming mounting flanges on all of the side walls and welding or bolting each mounting flange to the structure being bolted. One problem with this arrangement is that it is unnecessarily expensive and time consuming to fasten all four mounting flanges to the surface. In addition, in this type of arrangement, the nut is loose in the case and can be removed until such time that the cage and nut are attached to a surface. This is undesirable because it makes the mounting more difficult and makes it easier to lose the nut.
Another method for preventing spreading of the vertical walls of a caged nut employs a housing for the nut and a separate retaining member attached to the structure that engages and holds the side walls in place. This type of arrangement is expensive.
Still another method for retaining the vertical walls comprises mounting two end walls to the structure by means of mounting flanges extending therefrom and securing the position of the other walls by welding those walls to the fixed position walls. This method increases the cost of the assembly and still does not provide a method for holding the nut inside the housing at all times.
In still another method for retaining the vertical walls of a caged nut housing, the end walls have outwardly extending mounting flanges and the side walls have flanges that extend inwardly. The inner edges of these flanges are formed into upwardly extending semi-circular pilot flanges, which are disposed into an oversized volt clearance opening formed in the panel on which the caged nut is to be mounted. These pilot flanges restrain the outward movement of the side walls when the retainer is secured tightly to the panel.